The present invention relates to an input frequency control system of an electronic home appliance in the home automation system which transmits data by use of the frequency shift keying method, and more particularly to an automatic frequency control system which can control automatically the data being inputted to the electronic home appliance by detecting the frequency of the data being transmitted to the power line to identify whether the frequency is within the rated frequency range.
In general, the data being transmitted to the power line, in the home automation system, are inputted to electronic home appliances after having been converted into digital signals and the frequency thereof has been set in response to the resistance, which is a fixed value, of a variable resistor. Accordingly, in case that the frequency, which is a most important factor in the data transmission, is varied on occasion, error data may be transmitted to the electronic home appliances from the power line, moreover there may be sometimes occurred an occasion that data are not transmitted due to the frequency conversion, thereby causing the electronic home appliances to operate in error.